They are still more expensive than planes and there are fewer connections available, often not everyday of the week or only during certain times of year. But my biggest issue is that train companies don’t work together internationally so that there are no “official” connecting trains. You basically need to book them separately and if one is late you are screwed…
Don’t get me wrong, I like night trains and I use them, but there is still a long way to go to make them competitive against planes.
As someone who traveled from Germany to Italy by train and had a delayed austrian train:
There is an agreement between most european rail companies, that the next company will update your ticket if your previous one was delayed.
And the italian train company updated our ticket to a later one, because the austrian train was delayed by an hour and it was all booked online with DB. (the german train company)